1. Field of the Invention
The present invention relates to earphone technology, and more particularly, to an earphone having a passive radiator therein.
2. Description of the Related Art
Passive vibration diaphragm, also called as passive radiator, is normally mounted with a speaker in a cabinet to share the back cavity so that when the speaker converts electrical energy to sound waves, the air in the back cavity is compressed and transferred to the passive radiator, thereby indirectly driving the passive radiator to emit sound waves. Subject to the assistance of a passive radiator in a miniature speaker, the resonance effect of the back cavity is enhanced, and the overall performance of the sound field is optimized.
However, the applications of conventional passive radiators are mostly limited to large speakers without being seen in earphones. The back cavity of an earphone is relatively smaller, so its resonance and bass drop sound effects are limited. Therefore, downsizing a passive radiator for installation in an earphone can effectively optimize the overall audio performance of the earphone and enhance its competitiveness on the market.